The public switched telephone network's (PSTN) primary service has been to provide Plain Old Telephone Service (POTS), which has been accomplished using circuit switching technology and techniques. Traditionally, calls were established using circuits having defined bandwidth and characteristics suitable for voice transfer. In contrast, the Internet is a packet switched network designed for data transfer in which bandwidth can be allocated as needed. The PSTN and the Internet are evolving, to an extent, so as to adopt certain aspects and capabilities of the other.
One service that is involved in the evolution of both networks is voice traffic. At a high level, the traditional circuit switch telephone network is migrating towards transporting voice using packet switching technology. This offers the prospect of increased efficiencies and utilization of common equipment for voice, data, and video traffic. Similarly, the Internet that was initially developed to handle data transfer between computers has been adapted to carry voice calls. Various approaches have been created to convey voice over the Internet (“VoIP”), and many of the capabilities present in the PSTN are being adapted to VoIP environments
The proliferation of wireless telephones on relatively new networks that are entirely or at least in part digital-based has led to the advent of numerous features on wireless systems that are not available on traditional wireline systems. However, with the advent of advanced intelligent network (AIN) and computer switching on wireline systems and the use of VoIP in packet-switched networks such as the Internet, these wireless features are becoming possible and are being requested or demanded by the consuming public. Currently, for instance, when a telephone subscriber on a wireline or wireless phone calls another telephone subscriber, the caller hears audible ringing (a ring-back tone) until the called party answers the phone. Generally, the ring-back tone is a standard signal and sounds much like a telephone ringing. However, wireless subscribers are able in some instances to designate a certain tone, song clip or voice message to be played as a ring-back tone to all callers, designated groups of callers or individual callers. For example, Verizon Wireless of Bedminster, N.J. offers ring-back tones that may be purchased and downloaded through their website at http://ringbacktones.vzw.com/browse_2.jsp. This allows a subscriber to personalize their telecommunications service and such personalization is desirable to implement in wireline and VoIP telephone systems.